Please relay my “why” question to the customer. If they answer it, relay the
answer to me. (Or you can give my contact information to them and ask them to
contact me directly if you like.)
The answer to your question is, no, there is no way for a USB Audio 1.0 device
to convey a preferred format to Windows without a custom driver (or at least a
The device tells the driver what it supports; the driver tells Windows; and
Windows chooses the format that it thinks is best.
Windows thinks is 48 kHz is better than 8 kHz, and I tend to agree, hence my
From: wdmaudiodev-bounce@xxxxxxxxxxxxx <wdmaudiodev-bounce@xxxxxxxxxxxxx> on
behalf of Akshaykeerti Sharma <asharma@xxxxxxxxxxxxxxxxxxxxx>
Sent: Thursday, November 9, 2017 8:09:27 AM
Subject: [wdmaudiodev] Re: Change default sample rate windows
The customer wants to use default windows drivers, is there anyway in the USB
audio 1.0 spec to set a default sampling frequency without making any driver
For a lack of a better reason, the "spec" they provided us wants a default
value of 8Khz. This is for a bandwidth limited application and they would like
to have less data to process under most circumstances. Do you know where the
"Restore Defaults" gets its value from?
On 11/9/2017 9:55 AM, Matthew van Eerde (Redacted sender Matthew.van.Eerde for
You can write an .inf that wraps wdma_usb.inf but specifies
PKEY_AudioEngine_OEMFormat to favor 8 kHz 16 bit.
But why do you want to favor 8 kHz if the device supports 48 kHz?
behalf of Akshaykeerti Sharma
Sent: Wednesday, November 8, 2017 3:52:19 PM
Subject: [wdmaudiodev] Change default sample rate windows
I was wondering if there is a way to change the default sample rate on a
USB-audio peripheral on windows?
As for the current moment my new device enumerates at 48KHz/16bit. I would
prefer it to enumerate at 8KHz/16bit. The USB device supports both the sample
rates and it works fine when it is manually changed to 8KHz/16bit. I tried to
debug the device but it seems that I never get the "Get_cur" request for the
sampling rate when enumeration happens.. "Set_cur" works fine when I manually
change the sample rate and it sends the right request so I can manipulate the
firmware to go into 8KHz/48KHz mode.
Also, where does it get the "Restore Defaults" from. When I click it, the
system goes back to 48KHz/16bit.
Thanks for the help!
Simple Innovations, Inc.
(262) 246-9655 Ext 306